The present invention pertains generally to cushioned and upholstered support structures and, more particularly, to support structures which have multiple internal and assembled components.
A typical innerspring mattress includes an innerspring assembly having an array of interconnected coils of helical wire or other type of reflexive elements, one or more layers of material over the support surfaces of the innerspring, one or more layers of polymer foam over the support surfaces of the innerspring, and an upholstery layer covering these components. In a two-sided mattress, the support surfaces of both sides of the innerspring are covered with one or more layers of polymer foams, fiber batting and fabric layers of material such as cotton or wool. The internal layers are then encased in upholstery which is typically a quilted exterior layer, also referred to simply as upholstery or ticking. The seams of the upholstery layer are sewn together (often with tape edging) about the perimeter of the support surfaces. The edge or border of the innerspring between the support surfaces is similarly covered with upholstery, the edges of which are sewn to the edges of the support surface covers with a tape edge.
The upholstery material commonly has a quilted stitch pattern and a foam backing. This quilt stitch pattern is provided either by the upholstery material manufacturer, or in a mattress factory equipped with a quilt stitching machine, such as a Gribetz International, Kaybe, Emco or Matramatic type automated quilting machine, which have a linear array of controllable/programmable sewing needles and is programmable to sew any desired pattern into a swatch of material as it is passed under the array of needles. The decorative nature of the stitch pattern lends itself to application on the upholstery layer. However, any type or combinations of material penetrable by the the needles of the quilter are able to be sewn by such quilting machines. Prior to this invention, few if any applications of quilting machines have been made to the stitching of non-upholstery material layers or to any materials installed in the interior of a mattress.
Cushioning layers underneath the upholstery, including high density foam and man made fiber batts, in combination with other padded or quilted upholstery layers, can make the mattress very bulky and rounded at the edges. As a result, it is difficult to sew together the seams around the periphery of the mattress. This requires expert operation of a large tape edge stitching machine mounted at an oblique angle to the mattress. The sewing head must traverse the entire perimeter of the mattress, while keeping the internal layers of material in alignment. Thus, as the perimeter of the upholstery layer is stitched by the quilting machine, the cushioning layers within the mattress tend to shift, shifting the dimensions of the mattress as well. This is especially true of double-sided mattresses, with layers of cushioning material on both sides of the spring assembly. As the mattress layers shift, the dimensions of the mattress are skewed and the finished shape of the mattress is distorted. A method and construction for maintaining alignment of internal layers of a mattress during and after assembly is therefore desirable.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by various structures as covered by the patent claims.
The present invention provides a quilted internal mattress pillow which enhances dimensional stability of the mattress construction by quilt stitching one or more layers of internal material prior to installation or encapsulation by the mattress upholstery. By quilt stitching internal layers together, the alignment of the layers is maintained during final assembly and thereafter, and the support characteristics of the quilt-stitched internal layers are altered according to the stitch pattern. The quilted internal layer or layers do not shift relatively during stitching of the seams of the upholstery layer. In another aspect of the invention of quilt-stitching together internal layers of a mattress prior to assembly, the body of the quilted internal pillow may also contain a concentration of stitches in the lumbar or other areas to customize the support characteristics of the mattress.
In accordance with one general aspect of the invention, there is provided a quilted internal pillow which has at least one layer of supporting material and at least one layer of backing material quilted together prior to installation in a mattress. In one particular embodiment, the quilt-stitched internal layers are foam layers, and in a further embodiment one of the internal layers has a thickness or density greater than the other internal layer to which is it attached. One or more of the internal layers may be in the shape of a slab or planar piece, or have a convoluted surface, illustrating the principle that material layers of different configurations can be quilt-stitch attached to other layers by processing through automated quilt stitching machinery. Further, the quilting is performed by stitching the internal pillow, wherein the stitches extend through all layers of the quilted pillow to prevent lateral, longitudinal or sliding movement of the layers during handling and installation into the mattress.
The quilt stitching is preferably in a pattern or matrix located within the perimeter of the layers of the internal pillow, as compared to an edge or perimeter stitch. However, some of the stitches of the quilt-stitch pattern may be located proximate to the edges of the internal pillow layers so that the layers are adequately secured throughout. The quilt-stitching may be more concentrated in selected areas such as the lumbar area, thus, the higher concentration of stitching would create more density and support in that specific region. The internal quilted pillow is then inserted into a mattress between the upholstery layer and the spring assembly. The spring assembly includes an innerspring made of a plurality of springs or coils connected together in an array. In the case of a double-sided mattress, a second quilted internal pillow is inserted on the other side of the spring assembly, opposite to the first internal pillow to create a mattress with symmetrical sides of cushioning.
In accordance with another aspect of the invention, there is provided a quilted internal pillow which has at least one layer of supporting material and at least one layer of backing material quilted together and then inserted into a mattress. The quilted internal pillow is inserted into the mattress as a part of the pillow top. The innerspring is encased in the upholstery layer and stitched together. Thus, the mattress is stitched together by stitching the perimeter seams of the gusset and the pillow top together.
In an associated method of mattress manufacture of the present invention, a new use for the quilting machine is described. In the prior art, automated quilting machines are used exclusively to quilt-stitch the exterior upholstery layer of a mattress before it is installed as a cover over an innerspring and other materials. The present invention utilizes the quilting machine for quilt stitching together multiple layers of an internal mattress pillow, prior to installation of the pillow in a mattress. The quilt stitch patterns which may be used in the manufacture of the internal mattress pillows of the invention can be any of the patterns producible by the available machinery and control systems and software, and functional as attachment or fastening, and to alter the support characteristics of the internal mattress pillow.
These and other aspects of the present invention are herein described in further detail, with reference to the accompanying Figures, the illustrated embodiments being representative of only some of they ways in which the principles and concepts of the invention can be executed and employed.